DEFLECTION OF LIGHT—DYSON AND OTHERS. 137 
6. The track of the eclipse runs from North Brazil across the At- 
lantic, skirting the African coast near Cape Palmas, passing through 
the Island of Principe, then across Africa to the western shores of 
Lake Tanganyika. Inquiry as to the suitable sites and probable 
weather conditions was kindly made by Mr. Hinks. It appeared 
that a station in North Brazil, the Island of Principe, and’a station 
on the west of Lake Tanganyika were possible. A station near 
Cape Palmas did not seem desirable from the meteorological re- 
ports though, as the event proved, the eclipse was observed in a 
cloudless sky by Professor Bauer, who was there on an expedition 
to observe magnetic effects. At the station at Tanganyika it was 
thought the sun was at too low an altitude for observations of this 
character, owing to the large displacements which would be caused 
by refraction. 
A circular received from Doctor Morize, the director of the ob- 
servatory at Rio, stated that Sobral was the mosi suitable station in 
North Brazil and gave copious information of the meteorological con- 
ditions, mode of access, etc. 
7. Acting on this information the joint permanent eclipse com- 
mittee at a meeting on November 10, 1917, decided, if possible, to 
send expeditions to Sobral in North Brazil, and to the Island of 
Principe.. Application was made to the government grant committee 
for £100 for instruments and £1,000 for the expedition, and a subcom. 
mittee consisting of Sir F. W. Dyson, Professor Eddington, Profes- 
sor Fowler, and Professor Turner was appointed to make arrange- 
ments for the expeditions. This subcommittee met in May and June, 
1918, and made provisional arrangements for Professor Eddington 
and Mr. Cottingham to take the object glass of the Oxford astro- 
graphic telescope to Principe, and Mr. Davidson and Father Cortie 
to take the object glass of the Greenwich astrographic telescope to 
Sobral. It was arranged for the clocks and mechanism of the ccelo- 
stats to be overhauled by Mr. Cottingham. Preliminary inquiries 
were also set on foot as to shipping facilities, from which it appeared 
very doubtful whether the expeditions could be carried through. 
Conditions had changed materially in November, 1918, and at a 
meeting of the subcommittee on November 8, it was arranged to as. 
semble the instruments at Greenwich, and make necessary arrange- 
ments with all speed for the observers to leave England by the end 
of February, 1919. In addition to the astrographic object glasses fed 
by 16-inch celostats, Father Cortie suggested to the subcommittee 
the use of the 4-inch telescope of 19-feet focus, which he had used 
at Hernosand, Sweden, in 1914, in conjunction with an 8-inch ccelo- 
stat, the property of the Royal Irish Academy. It was arranged to 
